Bone-black kiln



NITED STATES PATENT Erica.

HERBERT ALLEN XVHEELER, OF ST. LOUIS, MISSOURI.

BONE-BLACK KILN.

SPECIFICATION forming part of Letters Patent No. 556,603, dated March 17, 1896.

ipplioation filed March 2, 1895 Serial No, 540,361- (No mod l.)

To all whom it may concern:

Be it known that I, HERBERT ALLEN WVHEELER, a citizen of the United States, residing at St. Louis, in the State of Missouri, have invented new and useful Improvements in Bone-Black Kilns, of which the following is a specification.

My invention relates to improvements in a kiln or furnace for calcining or charring ground bones into bone-black or for revivifying or restoring spent or used bone-black; and with that object in view my invention consists of the novel devices and combinations hereinafter described and specifically claimed.

In the accompanying drawings, Figure 1 is a longitudinal section through the kiln on the line 3 3. Fig. 2 is a cross-section through the kiln on the line 2 2. Fig. 3 is a plan of the kiln on the line 1 1; and Fig. 4is an enlarged longitudinal section through one of the au tomatic discharge-valves 5.

Similar letters and figures refer to similar parts throughout all the drawings.

The kiln or furnace is of the rectangular type, with vertical retorts R, and consists of a retort-chamber l3 and fireplace F, which are carried at a suitable elevation by the iron columns to permit the cooling of the freshlycalcined bone-black in the cooling-tubes T by having a free and unobstructed circulation of the air beneath the kiln.

The walls a of the kiln are carried on metal beams g, preferably of steel or iron, which are placed sufficiently below the heated portion of the kiln as to not be endangered by warping or bending from overheating. The walls are made of fire-brick or other material suitable for withstanding the heat employed in calcination. The walls and arches are suitably bound and braced with buck-staves and tie-rods in the usual manner, and there fore not herein shown in the drawings.

The fireplace F is situated at the lower part of one end of the retort-chamber B, and the chimney-flues P for the furnace-gases are situated at the sides of the upper part of the opposite end of the retort-chamber, as substantially shown. The fireplace has the usual fire doors G, ash-pit H and grate-bars. Two piers A rise from the bridgewvall to the furnace-arch, which form three ports D, D and D, and also protect the front retorts from being directly struck by the flames. These ports are so designed that while a portion of the heat and flames pass through the smaller side ports D D, and thence between the retorts and the sides of the retort-chamber, the greater portion of the heat and flames passes through the central port D, and thence between the two rows of retorts in the central portion of the retort-chamber, from whence to escape to the chimney-flues P at the sides of the end of the retort-chamber they must pass between the ends of the retorts, thus thoroughly heating the ends as well as the sides of the retorts.

Furthermore, the retorts are so spaced in a row that the distances between them through which the heat and gases from the central portion of the retort-chamber pass to get to the chimney-fines P on the sides are so arranged as to increase in width from the back end of the retort-chamber toward the front or fireplace, as shown at 4, 5, 6, 7, 8, 9, and 10. The object of this differential spacing of the retorts is to secure an equable distribution of the heat throughout the retort-chamber, as if equally spaced more of the heat tends to pass through the back spaces or passages 4, 5, and 6 than through the spaces or passages 8, 9, and 10 near the fireplace.

The retorts R are made of cast-iron or other suitable material, and are carried by flanges Q on metal beams g,which preferably are iron or steel. If the retorts are made of cast-iron, they have the flattened elliptical section or shape shown in Fig. 3. The tops of the retorts project slightly above the roof of the retort-chamber, and vapor-pipes 0 0 are fitted to them,which lead to a large central pipe or conduit 19, by means of which the vapors and odors are carried to any suitable condenser, scrubber, furnace or other means for collecting valuable vapors or gases, like ammonia, or for destroying and decomposing any noxious odors. The lower ends of the retorts project sufficiently below the retort-chamber to enable cooling-pipes T to be hung to them. These cooling pipes or tubes or receptacles for the hot calcined bone-black are made of sheetiron or other suitable material, and are sufficiently long that the hot bone-black after leaving the retort has sufficient time to so cool off in slowly passing through the cooling-tube that it will no longer ignite and burn into ashes when it is discharged into the air at the lower end, which otherwise happens it hot bone-black is exposed to the air.

The tops of the retorts pass through castiron rings or crown-holes m that are built into the arch of the retort-chamber substantially as shown, and these rings have the same shape or cross-section as the retorts, but are made sufficiently large as to give a free space of an inch or more between the inside of the ring and the sides of the retort. This free space enables the retorts to be easily and quickly set in position or removed. To prevent the air from leaking into the furnace through this free space, fire-clay stoppers or wedgers or spike-head-shaped pieces fit into these spaces n,which closes them completely after the retort has been put in place and lined up, or a packing of asbestos or mineral wool or other similar non-combustible material can be employed instead of the fire-clay wedges.

An inlet or orifice or opening 1' is made in the lower part of the vapor-pipes 0, the size of which is controlled by a sliding gate Lwhich works in grooves and is provided with a handle h. This automatically and continuously admits the ground bones or bone-black into the retorts from the hopper 10 that rests on top of the retort-chamber. This hopper w is filled by a cup elevator or eonveyer or similar automatic device, and by regulating the size of the orifice t by means of the sliding gate or valve I the material can be fed into the retorts at any desired speed.

The feed-hopper w is kept nearly full with the powdered bones or spent bone-black, and hence the gases, vapors and odors that are given of]? by the calcination in the retorts will rise up through the granular material in the retort to the vapor-pipes 0, and thence will pass to the large vapor-pipe 2) rather than escape through the small orifice i 011 account of the resistance of the column of material in the hopper w and the much-easier free escape through the large vapor-pipes 0. If necessary to positively prevent the escape of trifling quantities of odors through the inlet 2' when the hopper may be empty, an exhaustfan can be attached to the conduit 1), which will give a slight vacuum at i, and hence insure a positive inward flow of air at that point, with the prevention of the escape of any odors.

At the bottom of each of the cooling-pipes T are two small pipes that are provided with a rotary plug-valve 5, whose spindle or stem is moved by a slotted rocker-arm t, which by a pin .2 and nut y is moved to and fro by the oscillating slotted rod r,which latter, through the connecting-rod r, is moved forward and backward by the crank-wheel E, that is driven by any suitable mechanism. Fig. at is an e11- larged view of this automatic continuous adj ustable discharge device. By having the rocker-arm t and oscillating rod 1) slotted it is possible, by means of the pin .2 that passes through the slot of the rocker-ar1n t, to secure any amount of opening of the rotary valve 3 by sliding the nut y along the slotted oscillating rod o, as the nut y secures the pin .2 to the oscillating rod o. This device not only automatically regulates the speed of discharge of the calcined bone-black, but also enables each rotary valve to be set independently, and so permits the bone-black to be run out faster from the retorts near the fire place, which calcine more rapidly than those farther back, which do not get as much heat. The two small discharge-pipes on the bottom of each cooling-tube are placed near the ends, as substantially shown, to more rapidly discharge the bone-black from the sides of the retort, where it caleines more rapidly than in the central portion of the retort.

The cooling-pipes T discharge through the automatic rotary valves 5 into a receivinghopper X, which terminates in the boot of the cup elevator V, by which the calcined boneblack is automatically removed as fast as produced to storage-bins located at convenient places. A belt conveyor or screw, or

any other automatic conveying device, can.

be substituted for the cup elevator if more convenient.

The floor of the retort-chamber is arranged to secure non-conductivity of heat to the cooling-tubes below, to protect from heat the metal beams that carry the retorts, to permit the easy removal of retorts, and to secure economy of construction. The floor consists of fire-clay tiling cl or other suitable refractory material that is carried by light angleirons f that rest on the metal beams g that carry the side walls and retorts, and on top of the tiling is a thick layer of ashes, fire-clay, or other cheap refractory non-conductor. The joints between the retorts and tiling are made tight with asbestos, mineral wool, or other suitable non'conducting refractory packing material. Such a floor is easily taken up for renewing the retorts, is inexpensive, an d forms an excellent non-conductor.

Cleaning-doors l), as substantially shown, give easy access to the retort-chamber for purposes of inspection, cleaning, and repair.

Peep-holes c, substantially as shown, enable the temperature and condition of the retorts to be observed without jeopardizing or cracking the retorts from the admission of cold air, by being located on the back wall, under the chimney-fines P.

The size, height, and number of retorts to be heated in the retort-chamber will depend on the size of grain and character of the ground bones or spent bone-black to be calcined and on the amount to be treated, as will likewise the size of the fireplace, feeding gates, speed and size of the discharge-valves and elevators or conveyors.

\Vhat I claim as my invention, and desire to secure by Letters Patent, is-

1. The combination, in a bone-black kiln, of a retort-chamber having two rows of retorts, two chimney-flues at the upper part of one end, a fireplace at the lower part of the opposite end, two piers in the bridge-wall forming a large central port and two smaller side ports, with a differential spacing of the retorts to secure an equable heating of the ends and sides of the retorts, substantially as shown and described.

2. The combination, in a bone-black kiln with retorts, of a large feeding-hopper on top of the retort-chamber, vapor-pipes leading from the top of each retort to a central exhaust-conduit, inlets for the continuous, automatic admission of the material at the base of the Vapor-pipes, and a sliding gate to regulate the size of said inlet, as substantially shown. v

3. The combination, in a bone-black kiln with retorts, of cooling-tubes with small discharge-pipes, with rotary plug-valves within said discharge-pipes, a projecting spindle from each of said rotary plug-valves, a lever attached to each of said spindles, a pin and nut at the opposite end of each of said levers, a rock-shaft or oscillating rod to move said levers by the pins, a slot in said rock-shaft to secure an independent and adjustable movement to each spindle, and a connecting-rod and crank to oscillate or rock said slotted rock-shaft, substantially as shown.

In testimony whereof I hereunto affix my signature in the presence of two witnesses. I HERBERT ALLEN WHEELER.

Witnesses:

F. HENDERSON, ISAAC N. JUnsoN. 

